Los Angeles, CA water hardness
Los Angeles Department of Water and Power does not publish one hardness figure for Los Angeles. It publishes 3 separate figures, one per area, in its LADWP Water Quality FAQs, “How hard is my water?”. Across them the published numbers run from 93 to 291 mg/L. On the USGS scale those figures are not all in one class: they span moderately hard, hard and very hard water, so which class describes an address depends on which area serves it. Every published figure is in the table below.
Every figure Los Angeles Department of Water and Power publishes, by area
These are the only hardness numbers this utility publishes. There is no system-wide figure to quote, so the figure plotted above is a midpoint we calculated from the lowest and highest of them, and it is labelled as such everywhere it appears.
| Area as published | mg/L (ppm) | Grains per gallon | USGS class |
|---|---|---|---|
| San Fernando Valley and Western Los Angeles | 147, range 93–275 | 8.6, range 5.4–16.1 | Hard |
| Silver Lake, Downtown and South Los Angeles | 168, range 93–291 | 9.8, range 5.4–17 | Hard |
| Eastern Los Angeles and the Harbor | 279, range 275–281 | 16.3, range 16.1–16.4 | Very hard |
Figures in the grains column are the utility's own where it published them. Where it published only one unit, the other column is our conversion at 17.1 mg/L per grain, and the row above says which. Nothing in this table is averaged across areas.
The published figures, exactly as they appear
This is the hardness line transcribed from the source, with nothing added:
Hardness values by Water Quality Areas | Average | Range — San Fernando Valley and Western Los Angeles | 8.6 grains per gallon (147 mg/L as CaCO3) | 5.4 – 16.1 grains per gallon (93 – 275 mg/L as CaCO3); Silver Lake, Downtown and South Los Angeles | 9.8 grains per gallon (168 mg/L as CaCO3) | 5.4 – 17.0 grains per gallon (93– 291 mg/L as CaCO3); Eastern Los Angeles and the Harbor | 16.3 grains per gallon (279 mg/L as CaCO3) | 16.1 – 16.4 grains per gallon (275 – 281 mg/L as CaCO3)
Los Angeles Department of Water and Power, LADWP Water Quality FAQs, “How hard is my water?”
Units as published: grains per gallon, with mg/L as CaCO₃ given alongside. What kind of figure it is: a single value. Retrieved 2026-10-17.
Los Angeles hardness in mg/L and grains per gallon
Water-quality reports use mg/L (identical to ppm). Softener instructions and plumbing specifications use grains per gallon. Both are below. Where a figure is our arithmetic rather than the utility's own number, it says so.
| Figure | mg/L (ppm) | Grains per gallon | Whose number |
|---|---|---|---|
| Low end of published span across areas | 93 | 5.4 | both published by the utility |
| High end of published span across areas | 291 | 17 | both published by the utility |
| Plotted on the scale above | 192 | 11.2 | midpoint of the lowest and highest figures published across this system's 3 areas; the utility publishes no system-wide figure, so this midpoint is not one of its numbers; the gpg here is our conversion at 17.1, so it can differ slightly from a utility’s own rounded gpg figure |
The conversion, both ways: gpg = mg/L ÷ 17.1 and mg/L = gpg × 17.1. Worked for this system: 192 ÷ 17.1 = 11.2 gpg. The converter does °dH and °f as well, and why the factor is 17.1 explains where the number comes from.
What this figure does not tell you
Service area and source water
| Utility | Los Angeles Department of Water and Power |
|---|---|
| Service area as published | The City of Los Angeles, which LADWP divides into three water quality areas for this purpose. The FAQ states that most areas can receive any of LADWP's water supplies during repairs or emergencies. |
Provenance of every number on this page
| Source document | LADWP Water Quality FAQs, “How hard is my water?” |
|---|---|
| Source URL | https://www.ladwp.com/who-we-are/water-system/water-quality/water-quality-faqs |
| Published by | Los Angeles Department of Water and Power |
| Report year | 2022 |
| Year note | The FAQ answer introduces the figures with “The following information is from 2022”. The page itself carries no publication date. |
| Retrieved | 2026-10-17 |
| Classification bands | USGS Water Science School, retrieved 2026-10-16 |
Notes the report forces on this page
- LADWP publishes three area figures and no single system-wide figure. The plotted point on this page is the midpoint of the lowest and highest numbers across those three published ranges; it is not a number LADWP published. The area table above carries the numbers that are.
- The three areas do not share one classification. On the USGS bands used here, the San Fernando Valley and Western Los Angeles average of 147 mg/L and the Silver Lake, Downtown and South Los Angeles average of 168 mg/L are hard, and the Eastern Los Angeles and the Harbor average of 279 mg/L is very hard.
- LADWP prints its own guide on the same page — less than 4 grains per gallon soft, 4 to 7 medium-hard, greater than 7 hard. Those edges are not the USGS edges this site uses, and every LADWP area average is above 7 grains per gallon on LADWP's own scale.
- The figures are from 2022. The FAQ also notes that most areas can receive any of LADWP's supplies during repairs or emergencies, so which area figure describes an address can change.
If you are sizing a softener for Los Angeles water
At 11.2 gpg, the sizing arithmetic starts from your household's water use, not from the hardness alone. The calculator below is pre-filled with this system's figure and every other input is an editable assumption.
Whether a softener is worth installing at this hardness is a judgement, not arithmetic, and it is not one this site makes for you. Nothing here has been tested by the author.
Where Los Angeles sits against other verified systems
- Portland, OR 9 mg/L 0.5 gpg Soft
- Boston, MA 16 mg/L 1 gpg Soft
- Manchester, NH 17.9 mg/L 1 gpg Soft
- Raleigh, NC 25 mg/L 1.47 gpg Soft
- New York, NY 32 mg/L 2 gpg Soft
- Charlotte, NC 32 mg/L 1.9 gpg Soft
- Memphis, TN 46 mg/L 2.7 gpg Soft
- Anchorage, AK 56 mg/L 3.3 gpg Soft
- Oakland, CA 68.4 mg/L 4 gpg Moderately hard
- Nashville, TN 77.3 mg/L 4.5 gpg Moderately hard
- Sacramento, CA 83 mg/L 4.9 gpg Moderately hard
- Fresno, CA 89.3 mg/L 5.2 gpg Moderately hard
- Saint Paul, MN 90 mg/L 5 gpg Moderately hard
- Austin, TX 93 mg/L 5.4 gpg Moderately hard
- Washington, DC 95 mg/L 5.6 gpg Moderately hard
- Birmingham, AL 98 mg/L 5.7 gpg Moderately hard
- Kansas City, MO 100 mg/L 5.8 gpg Moderately hard
- Denver, CO 105 mg/L 6.1 gpg Moderately hard
- Tulsa, OK 114.5 mg/L 6.7 gpg Moderately hard
- Louisville, KY 115 mg/L 6.7 gpg Moderately hard
- Columbus, OH 120 mg/L 7 gpg Moderately hard
- Cleveland, OH 120 mg/L 7 gpg Moderately hard
- Philadelphia, PA 125 mg/L 7.3 gpg Hard
- Ann Arbor, MI 126 mg/L 7.4 gpg Hard
- Cincinnati, OH 133 mg/L 7.8 gpg Hard
- Milwaukee, WI 137 mg/L 8.01 gpg Hard
- St. Louis, MO 138 mg/L 8.1 gpg Hard
- Fort Worth, TX 145 mg/L 8.5 gpg Hard
- Honolulu, HI 162.5 mg/L 9.5 gpg Hard
- Wichita, KS 170 mg/L 9.9 gpg Hard
- Omaha, NE 170 mg/L 10 gpg Hard
- Los Angeles, CA 192 mg/L 11.2 gpg Very hard
- Lincoln, NE 192 mg/L 11.2 gpg Very hard
- Tampa, FL 220 mg/L 12.9 gpg Very hard
- Phoenix, AZ 237 mg/L 13.9 gpg Very hard
- Mesa, AZ 239.4 mg/L 14 gpg Very hard
- San Diego, CA 276 mg/L 16 gpg Very hard
- Las Vegas, NV 280 mg/L 16 gpg Very hard
- Chandler, AZ 282.2 mg/L 16.5 gpg Very hard
- San Antonio, TX 299.3 mg/L 17.5 gpg Very hard
- Anaheim, CA 300 mg/L 18 gpg Very hard
- Indianapolis, IN 317 mg/L 19 gpg Very hard
- Madison, WI 324.9 mg/L 19 gpg Very hard
- Scottsdale, AZ 352.5 mg/L 20.6 gpg Very hard
mg/L as calcium carbonate. Each classification band is drawn the same width, so the axis is not linear in mg/L.
Systems with similar published hardness
- Lincoln, NE Lincoln Water System, 192 mg/L (11.2 gpg)
- Wichita, KS City of Wichita Water Utilities, 170 mg/L (9.9 gpg)
- Omaha, NE Metropolitan Utilities District, 170 mg/L (9.9 gpg)
- Tampa, FL City of Tampa Water Department, 220 mg/L (12.9 gpg)
All 44 verified systems How to find hardness in your own utility's report If you are on a well instead